Electrical plug and pin structure



March v10, 1970 A. P. DE vn'o 3,500,299

ELECTRICAL PLUG AND PIN STRUCTURE Filed Feb. 29, 1968 I N VEN TOR.

ALE/5K7 A 05%70 BY M A N, VMTORNEYS United States Patent 3,500,299ELECTRICAL PLUG AND PIN STRUCTURE Albert P. DeVito, Niles, Ill.,assignor, by mesne assignments, to Conalco Metals, Inc., a corporationof Delaware Filed Feb. 29, 1968, Ser. No. 709,329 Int. Cl. H01r 9/08U.S. Cl. 339-220 Claims ABSTRACT OF THE DISCLOSURE An electrical plug ofthe quick detachable type has pin structures which are metal stamping'seach of which has a body of rectangular transverse cross-section closelyreceived within a complementary hole in the plug casting. On one end ofthe body is a shoulder engaging a face of the casting and providing asolder lug eye. Extending from the opposite end of the body and of thecasting is a contact pin. Also on such opposite end of the body is abendable integral locking lug which is bent over from original generalalignment with one edge of the body into locking opposition to theshoulder and to a portion of the casting engaged by and between theshoulder and the looking lug.

This invention relates in general to electrical connecting devices andis more particularly concerned with a new and improved stamped metal pinstructure for electrical plugs.

Various connecting pin arrangements have heretofore been employed inelectrical plugs of the quick-detachable type such as may be used foreffecting various electrical connections with and between panel boards,electronic components, replaceable module assemblies, and the like ineffecting electrical operating circuitry. Among prior devices have beenpin structures molded directly into the plug castings, force fit pininserts, cotter pin arrangements made of pin wire stock, and the like.While the cotter pin types of pin are quickly assembled, they sufiercertain disadvantages in that the wire stock must be of reasonably softmaterial to be readily worked in the wire forming dies and the pins arethus unduly susceptible to bending out of shape in subsequent handlingand manipulation by assembling tools. Further, the wire types of pin arediflicult to maintain in as straight alignment as desirable.

Accordingly, it is an important object of the present invention toprovide a new and improved pin structure for electrical plugs which iseconomically produced as a metal stamping in an easily assembled,reliable and effectively form-retaining construction.

Another object of the invention is to provide a novel stamped metalplug-carried pin structure having new and improved means for locking itin assembly with an electrical plug casting.

A further object of the invention is to provide a new and improvedbendable locking log for a structure adapted to be mounted in anelectrical pin casting.

A further object of the invention is to provide a new and improvedbendable locking lug for electrical plugcarried pins.

Still another object of the invention is to provide in an electricalplug, the quick-detachable type, a new and improved contact pinstructure and relationship.

Other objects, features and advantages of the present invention will bereadily apparent from the following detailed description of a preferredembodiment thereof taken into conjunction with the accompanying drawing,in which:

FIG. 1 is a side elevational view of an electrical plug embodyingfeatures of the invention.

Patented Mar. 10, 1970 ICC FIG. 2 is an enlarged fragmentary verticalsectional detail view taken substantially along the line II--II of FIG.1.

FIG. 3 is a fragmentary transverse sectional detail view takensubstantially along the line III--III of FIG. 2, and

FIG. 4 is a fragmentary plan view of a metal strip showing progressivesteps in the die stamping of the elec: trically conductive pinsembodying the invention.

An electrical plug 5 of the quick-detachable type embodying features ofthe invention comprises a dielectric body casting 7 carrying at leastone, and desirably a plurality of electrically conductive, suitablyspaced, stamped metal pins 8. While the plug body casting 7 is depictedas of the generally cylindrical type with the pins mounted in a circulararray, any other preferred geometrical form may be employed in thecasting and with any preferred orientation of the pins thereon. Ifdesired, the plug 5 may have a plug-in key stem 7a projecting from itsfront face.

According to the present invention, each of the pin structures 8 has abody 9 of substantially quadrangular cross section having opposite endportions, longitudinal edges along the body and opposite faces betweenthe edges. Receptive of the body 9 is a respective hole 10 (FIGS. 2 and3) which is of complementary quadrangular transverse cross section atleast throughout its length in firm engagement with the pin body 9 sothat in the assembly the pin structure is maintained firmly againsttransverse looseness. Thereby, a contact pin 11 extending as a fingerintegrally from one end portion of the body 9 and substantially beyondone end face of the plug casting 7 is maintained in accurateperpendicular alignment with respect to the plug axis and accuratelyspaced from the companion pins for efficient joining with a receptivesocket structure. Preferably the pin 11 is substantially an extension ofone longitudinal edge of the body 9 and is of generally cylindricalperimeter and has a generally rounded tip 12.

Means for positively locking the pin structure 8 to the plug casting 7against longitudinal displacement comprise fixed shoulder means on oneend portion of the body 9 and bendable locking lug means on the oppositeend portion of the body by and between which a portion of the plugcasting 7 is firmly engaged. In the illustrated example, the fixedshoulder means comprise a shoulder 13 normal to and extending out fromone of the longitudinal edges of the body 9 adjacent to the juncture ofan integral solder terminal lug 14 comprising an integral extension ofthat end portion of the body. This terminal is preferably of eye formhaving for this purpose an eye hole 15 therethrough. In the assembly,the shoulder 13 engages against the backened face of the casting 7 andfaces toward the opposite end portion of the pin structure. On suchopposite end portion of the pin structure and adjacent to the base ofthe pin finger 11 is an integral locking lug 17 which is bendable intolocking opposition to the shoulder 13 and to the portion of the plugcasting which is engaged by and between the locking lug and theshoulder.

In an efiicient, practicable form, the locking lug 17 is formedintegrally with the pin structure body 9 to be initially within theplane of the longitudinal edge of the body extending from the shoulder13, so that assembly of the pin structure with the casting 7 can bereadily effected by relative assembly movement wherein the pin finger 11and the body 9 are received within the bore of the hole 10 from the backface of the casting. Relative assembly movement continues until theshoulder 13 contacts the back face of the casting. Then, with the buttend of the solder lug 14 resting on an anvil surface A (FIG. 1) alocking lug clenching or bending tool applied to the locking lug drivestowards the anvil A, as indicated by the directional arrow T to bend thelocking lug onto a shoulder 18 facing generally outwardly from within asuitable lateral recess 19 provided-for this purpose intheforward H endface of the casting 7 alongside and as an extension of or from the boreof the hole 10. Although the locking lug 17 might be-bent out of theplane of either broad face of the body 9, a satisfactory and preferredarrangement comprises bending the locking lug in the plane of the body 9through the plane along the adjacent longitudinal edge of the body, asshown.

To facilitate bending of the locking lug 17 along a substantial arc freefrom abrupt bending point, and avoiding possible fracture and weakeningof the locking lug, it is shaped of gradually diminishing width from itsbase toward its free end. Further, along its shouldering edge 20, thelug 17 is desirably of concavely arcuate shape, which is accomplished byrecessing the edge of the body 9 adjacent to the base of the lockinglug. Along its opposite, inner, clenching tool-receiving edge 21, thelocking lug 17 is preferably convexly arcuate toward its tip and isseparated from the body 9 by a notch and converges toward, or divergesfrom the base of the pin finger 11. This assures controlled bending ofthe locking lug 17 into its clenching, clamping engagement with theshoulder 18 which, as shown, is ofconvexly rounded longitudinal contourconfronting the lug edge 20 and of a differential radius so as to beengageable effectively by the locking lug edge generally tangentiallyand substantially free from, and; with minimum danger of, fracturing therelatively rigid dielectric material of the casting 7 when the lug isbendably thrust into engagement therewith.

Manufacture of the pin structures 8 is effected economically by diestamping the same from a sheet metal blank 22 (FIG. 4) of suitably gaugestrip stock. The gauge of the material is desirably about the same asthe desired diameter of the pin fingers 11. Half hard brass stock hasbeen found excellent for the purpose. In progressive die stamping, theeye holes are punched in the strip and may serve as gauging pin holes inthe progress of the strip through the dies. Also punched in the strip 22are circular holes 23 which are oriented to provide the arcuate edges inthe subsequent stamping of pin structure. Thereafter, the pin structuresare partially blanked, and this may be accomplished by pluralities suchas five in each stroke of the dies. In this initial blanking out, thebody portions 9 and the locking lug 17 are completed and the pin fingers11 are rough blanked out. In the next stroke of the press, the five pinspreviously blanked out have the finger portions 11 thereof sized to thesubstantially cylindrical form. In the following stroke of the press,the pins are separated from the blank 22 by blanking out of the solderlugs 14, leaving characteristic openings 24 in the scrap of the blank.Thereafter, the completed pin structures may be plated, if desired, andare ready to be assembled with the casting 7 in the manner described. 7

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention.

I claim as my invention:

1. In a structure of the character described comprising an electricallyconductive stamped metal plug-carried pin:

a pin body of substantially quadrangular transverse cross section havingopposite end portions, longitudinal edges along the body and oppositefaces between said edges;

a contact pin finger projecting from one of the end portions of thebody;

a shoulder on one end portion of the body extending .4 I beyond one ofsaidedges andfacingrtoward the opposite end portion; and an integrallocking lug on said opposite end portion of the body normally withinsaid one edge to enable insertion of the pin into position on a plugbody by thrusting the pin through a hole in the plug body closelycomplementary in cross section to said pin body cross section; saidlocking lug being separated along an inner edge from said body by anotch, and said one longitudinal edge having a bend-facilitating recessadjacent the base of said lug whereby to facilitate bending of the lugout of and beyond said one longitudinal edge into locking opposition tosaid shoulder'and to a portion of the plug engaged by and between saidlug and said shoulder. v 2. A structure according to claim 1, saidlocking lug being on said pin body adjacent the juncture of said contactpin finger with said pin body, and said notch being between said fingerand said lug.

, 3. A structure according to claim 2, said finger being substantiallyan extension of the other of said longitudinal edges of the pin body.

4. A structure according to claim 3, said finger being sized to have asubstantially cylindrical cross section.

5. A structure according to claim 1, said lug having an arcuate edgealong said recess to facilitate bending of the lug.

6. A structure according to claim 1, said lug having an edge along saidnotch which is convexly arcuate toward the tip of the lug to facilitatebending of the lug.

7. A structure according to claim 1, said lug having a 1 concavelyarcuate edge along said recess and a convexly arcuate edge along saidnotch whereby to facilitate bending of the lug.

8. A structure according to claim 1, said locking lug being of graduallydiminishing width between said notch and said recess from the base ofthe lug toward the free end of the lug to avoid abrupt bending point inthe bending of the lug and thereby avoiding possible fracture andweakening of the lug during bending.

9. A structure according to claim 1, including, in combination with saidpin, a dielectric plug body casting having said hole in complementaryfirm engagement with said edges and faces of said pin body, saidshoulder engaging said casting at one end of said hole, said castinghaving an opposite end provided with a recess alongside said hole andwith a shoulder in said recess facing generally in the same'direction assaid pin shoulder and engaged by said locking lug substantially withoutfracture of the casting at the casting shoulder.

10; A structure according to claim 9, said lug having a concavelyarcuate edge confronting said casting shoulder,

and said casting shoulder being of convexly rounded contour confrontingsaid lug edge and of a differential radius such that the lug edgeengages the shoulder generally tangentially and substantially free fromfracturing the material of the casting at the shoulder.

References Cited UNITED STATES PATENTS 1,716,144 6/1929 Morrison 339-2152,316,555 4/1943 Bugg 339-215 XR 3,109,689 11/1963 Cooney.

3,241,097 3/1966 Ege.

KENNETH DOWNEY, Primary Examiner

